The present invention provides an absorption cooling system that can be operated utilizing relatively low grade heat sources e.g., solar energy, low-grade steam source, and industrial processes exhaust heat.
Typical absorption cooling systems utilize a heat source to vaporize under pressure a refrigerant material from a rich solution (generator/desorber). The pressurized desorbed refrigerant is then condensed by rejecting heat from it to the ambient surrounding, and it is then used for cooling by evaporating it under lower pressure conditions, whereby ambient heat is absorbed from the refrigerated space. The evaporated refrigerant is then absorbed back into the weak solution (absorber) to provide a reconstituted (rich) solution as the process is continuously repeated.
U.S. Pat. No. 4,171,619 describers a refrigeration system wherein heat from a solar energy source heats a refrigerant and absorbent solution in a generator to provide a refrigerant vapor to condensing and evaporating means, and wherein a compressor is used to compress vapor passing from the evaporator to the absorber, or between the evaporator and the condenser, and a pump is used for pressurizing the reconstituted solution obtained from the absorber. In this refrigeration system however a cooling tower is required for providing cooling water to the absorber and condenser.
WO 2007/110854 describes a vehicle air conditioning system utilizing an absorption compressor designed to work in parallel with a conventional mechanical compressor, wherein heat energy from the vehicle exhaust gas is used by the air conditioning system as a heat source. The absorption cycle in this international application is very simple providing compression cycle mode or simple absorption sub cycle functioning in place of the compressor, while the rest part of the refrigerant sub cycle remain the same. In addition, nor the absorption system or the compression cycle in this air conditioning system is used for heating the vehicle.
The methods described above have not yet provided satisfactory air cooled absorption cooling systems operated by low grade heat.
It is therefore an object of the present invention to provide systems and methods for absorption cooling that can be efficiently operated employing air as a cooling medium.
It is another object of the present invention to provide systems and methods for absorption cooling that can be efficiently operated utilizing low grade heat sources.
Other objects and advantages of the invention will become apparent as the description proceeds.